Isoproterenol attenuates high vascular pressure-induced permeability increases in isolated rat lungs

attenuates high vascular pressure-induced permeability in-creases in isolated rat lungs. J. Appl. Physiol. 83(6): 1962– 1967, 1997.—To separate the contributions of cellular and basement membrane components of the alveolar capillary barrier to the increased microvascular permeability induced by high pulmonary venous pressures (Ppv), we subjected isolated rat lungs to increases in Ppv, which increased capillary filtration coefficient (Kfc) without significant hemor-rhage (31 cmH2O) and with obvious extravasation of red blood cells (43 cmH2O). Isoproterenol (20 µM) was infused in one group (Iso) to identify a reversible cellular component of injury, and residual blood volumes were measured to assess extravasation of red blood cells through ruptured basement membranes. In untreated lungs (High Ppv group), Kfc in-creased 6.2 6 1.3 and 38.3 6 15.2 times baseline during th